My first thought is the grey one was her mom's favourite (because she looked most like her), and that + being abandoned by the same mom caused some issues, mostly around her self-worth and identity (was she no longer good enough? If her mom always told her how much like her she was, does that mean she's all the awful things her siblings call her mom too?)

Bottom one is overly positive to the point of being harmful. Their mother abandoned them, and they don't want their loved ones to ever feel the pain of their kin hurting them again, which causes them to keep any negative feeling they have to themself, and allowing those they love to get away with things they shouldn't in fear of hurting them with confrontation.

Red girl is cold to anyone she doesn't know. Not wanting to be betrayed again, she keeps her friends and (trusted) family close and everyone else far, far away. She focuses on training her combat skills, especially when she feels negative because it's a good distraction. She's also very suspicious of anyone who even speaks to her siblings, and will often try to scare them away--which doesn't exactly make her siblings happy (but bottom sibling would rather live with the heartache than say anything). She's also so busy thinking of protecting them and herself from harm that she neglects letting herself experience all the good that comes with new relationships

BUT @starfalcon555 had an idea that the kits were abandoned because Doveflame noticed they look like Hawk, and this time she left them in fear of them coming back to hurt her (sure that this time they would die).

One has Hawk's markings, another is red like him. It makes sense for Doveflame to leave those two, but keep the kit that resembled her. Treat her well, shower her with praise because oh she looks so much like her mother, and then leave her when she was no longer useful.

Red girl and bottom sibling in this case wouldn't have nearly as much issues, because they would have been found while still newborns and would have been cared for by Hawk and his family. Mini Dove would also have the startling realization that her perfect mum was horrible far before she left her--she abandoned her littermates when they were born and never told her about them, then left her too.

I'm conflicted because the second option makes more sense for Doveflame's character and is extra background for mini Dove, but the first option allows all of their personalities and issues to be expanded on

Or maybe the bottom sibling had that thing where markings grow over time, so the Hawk-like markings only showed up when they were a bit older?

Also if Doveflame kept them, she would have definitely treated the other two worse for the crime of kinda looking like their half-brother.

(as for who is who, you can decide!)

BASES:

--Red base by Crucifiedpup on Toyhouse

--Brown base by Hypervantie on DeviantArt